GATE ECE

Semiconductor Physics

Electronic Devices and Vlsi

(Past Years Questions)

Marks 1

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A bar of Gallium Arsenide (GaAs) is doped with Silicon such that the Silicon atoms occupy Gallium and Arsenic sites in t...
GATE ECE 2017 Set 1
A small percentage of impurity is added to an intrinsic semiconductor at 300 K. Which one of the following statements is...
GATE ECE 2016 Set 1
An n–type silicon sample is uniformly illuminated with light which generates 1020 electron hole pairs per cm3 per second...
GATE ECE 2015 Set 2
A piece of silicon is doped uniformly with phosphorous with a doping concentration of $$10^{16}/cm^2$$. The expected val...
GATE ECE 2015 Set 2
A silicon sample is uniformly doped with donor type impurities with a concentration of $$10^{16}/cm^3$$.The electron and...
GATE ECE 2015 Set 1
In the figure ln(ρi) is plotted as a function of 1/T, where ρi the intrinsic resistivity of silicon, T is is the tempera...
GATE ECE 2014 Set 4
The cut-off wavelength (in µm) of light that can be used for intrinsic excitation of a semiconductor material of bandgap...
GATE ECE 2014 Set 4
A thin P-type silicon sample is uniformly illuminated with light which generates excess carriers. The recombination rate...
GATE ECE 2014 Set 3
At T = 300 K, the hole mobility of a semiconductor $$\mu_p\;=500\;cm^2/V-s$$ and $$\frac{kT}q\;=\;26\;mV$$.The hole diff...
GATE ECE 2014 Set 3
Drift current in the semiconductors depends upon
GATE ECE 2011
Which of the following is true?
GATE ECE 2008
Under low level injection assumption, the injected minority carrier current for an extrinsic semiconductor is essentiall...
GATE ECE 2006
The concentration of minority carriers in an extrinsic semiconductor under equilibrium is:
GATE ECE 2006
The primary reason for the widespread use of Silicon in semiconductor device technology is
GATE ECE 2005
A Silicon PN junction at a temperature of 20°C has a reverse saturation current of 10 pico-Amperes (pA). The reverse sat...
GATE ECE 2005
The band gap of Silicon at room temperature is:
GATE ECE 2005
The impurity commonly used for realizing the base region of a silicon n-p-n transistor is
GATE ECE 2004
n-type silicon is obtained by doping silicon with
GATE ECE 2003
The band gap of silicon at 300 K is
GATE ECE 2002
The intrinsic carrier concentration of silicon sample at 300oK is $$1.5\times10^{16}/m^3$$. If after doping, the number ...
GATE ECE 2002
The units of $$\frac q{KT}$$ are
GATE ECE 1997
The probability that an electron in a metal occupies the Fermi-level at any temperature (> 0 K)
GATE ECE 1995
The drift velocity of electrons in silicon
GATE ECE 1995
In a P-type silicon sample, the hole concentration is $$2.25\times10^{15}/cm^3$$. If the intrinsic carrier concentratio...
GATE ECE 1995
A p-type silicon sample has a higher conductivity compared to an n-type sample having the same dopant concentration.
GATE ECE 1994
A small concentration of minority carries is injected into a homogeneous semiconductor crystal at one point. An ele...
GATE ECE 1994

Marks 2

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The dependence of drift velocity of electrons on electric field in a semiconductor is shown below. The semiconductor has...
GATE ECE 2017 Set 1
A dc voltage of 10V is applied across an n–type silicon bar having a rectangular cross–section and a length of 1cm as sh...
GATE ECE 2015 Set 2
Consider a silicon sample doped with ND = 1×1015/cm3 donor atoms. Assume that the intrinsic carrier concentration ni = 1...
GATE ECE 2014 Set 4
An N-type semiconductor having uniform doping is biased as shown in the figure. If EC is the lowest energy level of th...
GATE ECE 2014 Set 4
Assume electronic charge q = 1.6×10-19 C, kT/q = 25 mV and electron mobility μn = 1000 cm2/V-s. If the concentration gra...
GATE ECE 2014 Set 2
The silicon sample with unit cross-sectional area shown below is in thermal equilibrium. The following information is gi...
GATE ECE 2010
The silicon sample with unit cross-sectional area shown below is in thermal equilibrium. The following information is gi...
GATE ECE 2010
A silicon sample 'A' is doped with 1018 atoms/cm3 of Boron. Another sample 'B' of identical dimensions is doped with 101...
GATE ECE 2005
The electron concentration in a sample of uniformly doped n-type silicon at 300oK varies linearly from $$10^{17}/cm^3$$ ...
GATE ECE 2003
An n-type silicon bar 0.1 cm long and $$100\;\mu m^2$$ in cross-sectional area has a majority carrier concentration of $...
GATE ECE 2003
A semiconductor is irradiated with light such that carriers are uniformly generated throughout its volume. The semicondu...
GATE ECE 1992
A silicon sample is uniformly doped with 1016 phosphorous atoms/cm3 and 2 ×1016 boron atoms/cm3. If all the dopants are ...
GATE ECE 1991
In an intrinsic semiconductor the free electron concentration depends on
GATE ECE 1987

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